package com.example.service;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import java.io.IOException;
import java.util.*;

/**
 * Author wangJinLong
 * Date 2025/8/1 14:46
 **/
public class WordCount {

    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        conf.set("fs.defaultFS", "hdfs://mycluster"); // 指向你的 HA 集群
//        conf.set("user.name", "vagrant");

        // 或者直接指向 NameNode（非 HA）
//         conf.set("fs.defaultFS", "hdfs://hadoop01:9000");

        FileSystem fs = FileSystem.get(conf);

        // 上传文件
        fs.copyFromLocalFile(new Path("data/file.txt"), new Path("/user/hp"));
    }

    public static void testMapReduce() {
        List<Integer> integerList = Arrays.asList(1, 2, 3, 4, 5);
        Integer total = integerList.stream()
                .map(x -> x * x)
                .reduce(Integer::sum).get();
        System.out.println(total);
    }


    public static void extracted() throws IOException, InterruptedException, ClassNotFoundException {
        String[] args;
        args = new String[]{"data/input", "data/output"};
        Configuration conf = new Configuration();
        Job job = Job.getInstance(conf, "word count");
        job.setJarByClass(WordCount.class);
        job.setMapperClass(TokenizerMapper.class);
        job.setCombinerClass(IntSumReducer.class);
        job.setReducerClass(IntSumReducer.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);
        FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }

    public static class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable> {
        private final static IntWritable one = new IntWritable(1);
        private Text word = new Text();

        public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
            System.out.println("TokenizerMapper map value: " + value);
            StringTokenizer itr = new StringTokenizer(value.toString());
            while (itr.hasMoreTokens()) {
                word.set(itr.nextToken());
                context.write(word, one);
            }
        }
    }

    public static class IntSumReducer extends Reducer<Text,IntWritable,Text,IntWritable> {
        private IntWritable result = new IntWritable();

        public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException {
            System.out.println("IntSumReducer reduce values: " + values);
            int sum = 0;
            for (IntWritable val : values) {
                sum += val.get();
            }
            result.set(sum);
            context.write(key, result);
        }
    }

}
